Overall objectives of this proposed investigation for the next grant period are: (1) to develop efficient, highly stereochemically controlled methods for the synthesis of steroid side chains and the C/D-ring portion of physilogically important steroids. These include vitamin D3 and its metabolites, adrenosterone, pregnenolone, cholesterol and its metabolites, insect molting hormones and some plant hormones; (2) as an extension of the first objective, to explore novel, generally applicable methodologies towards the synthesis of acyclic carbon chain systems. We would like to continue our synthetic endeavors towards the general objectives described above with the following specific aims: (a) synthesis of appropriately functionalized hydrindanes for the synthesis of vitamin D3 metabolites, pregnenolone, and 11-keto steroids such as adrenosterone, (b) completion of the synthesis of the plant hormone oogoniols, (c) application of the ene reactions and the novel 1 less than 3- and 1 less than 3,4-chirality transmission method using the radical cyclization reactions to the synthesis of vitamin D3 metabolites and 22-hydroxy side chains of steroids present in alpha-eodysone (insect molting hormone) and the anti-tumor agent withaferin A, (d) synthesis of the termite pheromone biflora-4,10(19),15-triene using the Carroll reaction, (e) synthesis of natural 1,3-dimethylated acyclic chains, (f) application of chirality transfer reactions to the synthesis of natural 1,3,5-trimethylated acyclic chains including Prelog-Djerassi lactone and invictolide, (g) development of the novel, tandem-conjugate addition-[2,3]-Wittig rearrangement sequence as an entry to acyclic stereocontrol.